In order to detect a shaft shear or an over-speed condition, a probe is typically provided as close as possible to the power turbine. However, this area is a hot zone where probe failure is more likely. To reduce the risk of failure for the probe, it may be located further away from the power turbine. However, this can make certain sections of the shaft more difficult to accurately monitor, thus making the detection system less reliable.
Therefore, there is a need for improvement in shaft shear and over-speed detection systems.